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NTIS

06/13/1991

Collation

17p

Abstract

The persistence and interaction between newly isolated strains of Pseudomonas aeruginosa and resident bacteriophages indigenous to a freshwater environment was monitored over 45 days in lake water microcosms. The interaction between susceptible and resistant bacteria with pure phage (UT1) particles or a mixed phage population (M1) was investigated by following temporal changes in host density, phage-to-bacteria ratio (PBR), and the appearance of apparent prophage carriers within the host population. Decay rates of the phage (UT1) ranged from 0.054/hour in natural water to 0.027/hour in natural water to 0.027/hour in filtered lake water. About 45% of sensitive bacteria incubated with phase UT1 were pseudolysogenic within 12 hours of incubation in natural lake water. Phage UT1 appeared to stabilize the density of host bacteria in lake water at a level of 10 to the fourth power colony-forming units (cfu)/ml. Bacterial coexistence with the mixed phage (M1) population resulted in an oscillating equilibrium with the PBR stabilizing at about 3. (Copyright (c) Springer-Verlag New York, Inc. 1990.)